xxxvi Field Columbian Museum — -Zoology, Vol. V. 



RIO PANUCO SYSTEM. 



The Rio Panuco is a very large stream flowing into the Gulf at 

 Tampico. Some of its upper tributaries drain a portion of the central 

 plateau, from which it reaches the main river through a gap in the 

 mountains by a series of cascades and falls. Near the mouth of the 

 Rio Panuco are several large salt or brackish water lagoons. The tide 

 backs up into the river and lagoons to some distance above the city 

 of Tampico. There have been only a few collections of fishes made 

 in this river basin. 



The Rio Forlon, which at Forlon is a small stream in the dry 

 season, flows over a rocky and gravelly bed. 



The Rio Valles at Valles is a broad and rather sluggish stream 

 flowing past the city over a rocky bed; for some distance above it is 

 deep and has a muddy bottom. 



A tributary of the Rio Valles at Rascon has a more rapid current, 

 and its water is very clear. It flows through a narrow valley in which 

 is a dense forest of palms, mesquite, and thickets of canes, ferns, and 

 vines. 



The Rio San Juan, at San Juan del Rio, becomes nearly dry in the 

 dry season, as does also the Rio Tula at Tula. I spent one day at San 

 Juan del Rio in May, 1 901, collecting fishes. I found here but three 

 species,* which properly belong to the fauna of the Rio Lerma. 



Dr. W. L. Tower made a small collection in 1904 in the Rio Verde 

 at Rio Verde. Except a few fishes taken by Dr. A. Dug6s in Huas- 

 teca Potosina in northeastern Guanajuato, collections of fishes have 

 been made in this river basin only at the places mentioned above. 



Of the thirty-two species recorded from this river basin, fifteenf 

 belong to the northern fauna, the others are tropical. 



Below is given a list of the fishes known from the Rio Panuco and 

 its tributaries: 



tLepidosteus osseus ( Linnaeus) : Forlon; Valles; Tampico. 

 tLepidosteus tristoechus (Bloch & Schneider): Tampico; "Tamaulipas." 

 jlchthyaelurus furcatus (Le Sueur) : Tampico. 

 jTchthyaslurus punctatus (Rannesque) : Forlon. 

 tAmiurus australis Meek: Forlon. 

 jAmiurus mexicanus Meek: Rio Verde; Rascon. 

 fCarpiodes tumidus Baird & Girard: Forlon; Tampico. 

 fCarpiodes labiosus Meek: Valles. 



*Algansea tincella (Cuvier & Valenciennes) : San Jvtan del Rio. 

 tHybognathus rasconis (Jordan & Snyder): Rio Verde; Rascon; Valles; Forlon. 

 ;,: Aztecula mexicana Meek: San Juan del Rio. 

 tNototropis forlonensis Meek: Forlon; Valles. 



Tetragonopterus mexicanus Filippi: Rascon; Valles; Forlon; Rio Verde; Tam- 

 pico. 

 fDorosoma exile Jordan & Gilbert: Forlon; Valles. 



